The present invention was developed by necessity created by the inability of an existing radar system to function properly within its environment. The cross-field amplifier used within the radar system has a tendency to a high rate of failures. One reason for these failures is that the thermionic emitter cathode of the amplifier, which operates on the principle of direct heating to boil off electrons, tends to arc when started cold. Start-ups thus creates an instability wherein the cathode has a tendency to arc which cause damage to the crossed-field amplifier.
A crossed-field amplifier of the thermionic emitter type has been utilized in many existing radar systems for several years. Thus, any design change of the amplifier must be capable of a retrofit into the existing radar facility.
It has been known for approximately ten years that a so-called long circuit crossed-field amplifier utilizing a pure platinum emitter can meet the stability requirements of the existing equipment. However, a platinum emitter is a secondary emitter that requires the acceleration of electrons toward a larger emitter to drive off additional electrons which spin toward the anode. This larger sized emitter makes it difficult to retrofit into an existing radar system. Further, because of the need to liquid cool the platinum emitter, the hardware necessary to accomplish the retrofit does not fit into the existing equipment space.